Mute control circuit used upon power-on or power-of, control method, and audio device

ABSTRACT

A mute control circuit used upon power-on or power-off comprises a charge/discharge module, a first switch module and a second switch module. Upon power-on or power-off, charging or discharging is performed between the charge/discharge module and a power supply end. Upon charging or discharging, the charge/discharge module outputs a first level to the first switch module to control turning on of the same, and the first switch module outputs a second level to the second switch module to control turning on of the second switch module, such that the second switch module outputs a high level to a mute circuit to activate operation of the mute circuit. Also provided are a control method and an audio device.

This application claims the benefit of priority of a China PatentApplication No. 201710679849.X submitted to State Intellectual PropertyOffice of the P.R.C. on Aug. 10, 2017, entitled “MUTE CONTROL CIRCUITUSED UPON POWER-ON OR POWER-OF, CONTROL METHOD, AND AUDIO DEVICE”, thecontents of which are incorporated herein by reference in theirentirety.

TECHNICAL FIELD

The present invention relates to audio device technologies, and moreparticularly to a mute control circuit used upon power-on or power-off,a control method and an audio device.

DESCRIPTION OF RELATED ARTS

For current products with a sound box or a speaker, it is easily to havea pop sound upon power-on, at the time some coupling capacitors of acentral process unit (CPU) and a power amplifier system are beingcharged. Upon power-off, discharging processes of the couplingcapacitors may cause the pop sound easily. If the pop sound is not undercontrol, it is possible to cause damage of a device upon system power-onor power-off. The existence of the pop sound also has a great impact onproduct experience. For a good audio product, sound is outputted onlywhen the system normally produces a sound and it should always be mutedupon power-on and power-off.

Audio products generally have a software control system. Due to theexistence of a micro central unit (MCU), the software can control thevoltage level of enable pins via an input/output (IO) port in normaloperations of the system; however, the IO port is uncontrollable uponsystem power-on and power-off. Therefore, it is necessary to implementcontrolling the voltage level of the enable pins by hardware, therebycontrolling the generation of pop sound.

Therefore, the existing arts are needed to be improved.

SUMMARY Technical Problems

Embodiments of the present invention provide a mute control circuit usedupon power-on or power-off, a control method and an audio device, inwhich a low-cost and easily controlled circuit is adopted to be able tooutput high voltage level to a mute circuit upon power-on and power-offto control the mute circuit to be activated, thereby eliminating the popsound generated upon power-on or power-off, and improving userexperience on the audio devices.

Technical Solutions

In a first aspect, the embodiments of the present invention provide amute control circuit used upon power-on or power-off, connected to apower supply end and a mute circuit of an audio device, wherein the mutecontrol circuit used upon power-on or power-off includes acharge/discharge module, a first switch module and a second switchmodule; upon power-on, the charge/discharge module is charged from thepower supply end, upon power-off, the charge/discharge module dischargesinto the power supply end, upon charging or discharging, thecharge/discharge module outputs a first level to the first switch moduleto control the first switch module to be in a turned-on state, the firstswitch module outputs a second level to the second switch module tocontrol the second switch module to be in the turned-on state, thesecond switch module outputs high voltage level to the mute circuit tocontrol the mute circuit to be activated.

Further, in the mute control circuit used upon power-on or power-off,the charge/discharge module includes a charge/discharge unit and aseparation unit, the separation unit controls a charging currentdirection and a discharging current direction upon power-on andpower-off, the charge/discharge unit performs charging or dischargingbased on the charging current direction and the discharging currentdirection.

Further, in the mute control circuit used upon power-on or power-off,the charge/discharge unit includes a first capacitor and a secondcapacitor, the separation unit includes a first diode, a second diodeand a first resistor; a positive electrode of the first diode isconnected to a negative electrode of the second diode, one end of thefirst resistor and the power supply end, the negative electrode of thefirst diode is connected to the first switch module and the secondswitch module and is further grounded via the second capacitor; thepositive electrode of the second diode is connected to the other end ofthe first resistor and the first switch module and is further groundedvia the first capacitor.

Further, in the mute control circuit used upon power-on or power-off,the first switch module includes a second resistor, a third resistor anda first triode; one end of the second resistor is connected to thepositive electrode of the second diode and the other end of the secondresistor is connected to a base electrode of the first triode; anemitter electrode of the first triode is connected to one end of thethird resistor and the other end of the third resistor is connected tothe negative electrode of the first diode, a collector electrode of thefirst triode is connected to the second switch module.

Further, in the mute control circuit used upon power-on or power-off,the second switch module includes a fourth resistor, a fifth resistorand a second triode; one end of the fourth resistor is connected to thecollector electrode of the first triode and the other end of the fourthresistor is connected to the base electrode of the second triode; thecollector electrode of the second triode is connected to the negativeelectrode of the first diode and the emitter electrode of the secondtriode is connected to one end of the fifth resistor and the mutecircuit; the other end of the fifth resistor is grounded.

Further, in the mute control circuit used upon power-on or power-off,the first triode is a PNP triode.

Further, in the mute control circuit used upon power-on or power-off,the second triode is an NPN triode.

In a second aspect, the embodiments of the present invention furtherprovide a mute control method used upon power-on or power-off, whichincludes steps of:

upon power-on charging or power-off discharging, utilizing acharge/discharge module to output a first level to a first switch moduleto control the first switch module to be in a turned-on state;

utilizing the first switch module to output a second level to a secondswitch module to control the second switch module to be in the turned-onstate;

utilizing the second switch module to output high voltage level to amute circuit to control the mute circuit to be activated.

In a third aspect, the embodiments of the present invention furtherprovide an audio device, including a power supply end, a mute circuitand a mute control circuit used upon power-on or power-off, the mutecontrol circuit used upon power-on or power-off is connected to thepower supply end and the mute circuit;

the mute control circuit used upon power-on or power-off includes acharge/discharge module, a first switch module and a second switchmodule; upon power-on, the charge/discharge module is charged from thepower supply end, upon power-off, the charge/discharge module dischargesinto the power supply end, upon charging or discharging, thecharge/discharge module outputs a first level to the first switch moduleto control the first switch module to be in a turned-on state, the firstswitch module outputs a second level to the second switch module tocontrol the second switch module to be in the turned-on state, thesecond switch module outputs high voltage level to the mute circuit tocontrol the mute circuit to be activated;

the first level is low voltage level and the second level is highvoltage level.

Further, in the audio device, the charge/discharge module includes acharge/discharge unit and a separation unit, the separation unitcontrols a charging current direction and a discharging currentdirection upon power-on and power-off, the charge/discharge unitperforms charging or discharging based on the charging current directionand the discharging current direction.

Further, in the audio device, the charge/discharge unit includes a firstcapacitor and a second capacitor, the separation unit includes a firstdiode, a second diode and a first resistor; a positive electrode of thefirst diode is connected to a negative electrode of the second diode,one end of the first resistor and the power supply end, the negativeelectrode of the first diode is connected to the first switch module andthe second switch module and is further grounded via the secondcapacitor; the positive electrode of the second diode is connected tothe other end of the first resistor and the first switch module and isfurther grounded via the first capacitor.

Further, in the audio device, upon power-on at the power supply end, thefirst capacitor is charged from the power supply end via the firstresistor and the second capacitor is charged from the power supply endvia the first diode, low voltage level is outputted to the first switchmodule during charging the first capacitor; upon power-off at the powersupply end, a discharging path from the second capacitor to the powersupply end is isolated due to an isolation function of the first diode,such that electric charges in the second capacitor are dischargedthrough the first switch module, and the electric charges in the firstcapacitor are released through the second diode, making a voltage signaloutputted to the first switch module at low voltage level, therebycontrolling the first capacitor and the second capacitor to performcharging or discharging according to a preset path.

Further, in the audio device, the first switch module includes a secondresistor, a third resistor and a first triode; one end of the secondresistor is connected to the positive electrode of the second diode andthe other end of the second resistor is connected to a base electrode ofthe first triode; an emitter electrode of the first triode is connectedto one end of the third resistor and the other end of the third resistoris connected to the negative electrode of the first diode, a collectorelectrode of the first triode is connected to the second switch module.

Further, in the audio device, the second switch module includes a fourthresistor, a fifth resistor and a second triode; one end of the fourthresistor is connected to the collector electrode of the first triode andthe other end of the fourth resistor is connected to the base electrodeof the second triode; the collector electrode of the second triode isconnected to the negative electrode of the first diode and the emitterelectrode of the second triode is connected to one end of the fifthresistor and the mute circuit; the other end of the fifth resistor isgrounded.

Further, in the audio device, the first triode is a PNP triode.

Further, in the audio device, the second triode is an NPN triode.

Further, in the audio device, upon power-on at the power supply end, avoltage signal inputted to the base electrode of the first triode is atlow voltage level, a power supply voltage at the power supply endreaches the emitter electrode of the first triode via the first diodeand the third resistor, when a voltage difference between the emitterelectrode and the base electrode of the first triode is greater than0.7V, the turned-on state maintains for the first triode and both ofvoltages of the collector electrode of the first triode connected to thebase electrode of the second triode and the emitter electrode of thefirst triode are at high voltage level such that the first switch moduleoutputs high voltage level to the second switch module; since theemitter electrode of the second triode is grounded, the second triode iscontrolled to be in the turned-on state and both of voltages of theemitter electrode and the collector electrode of the second triode areat high voltage level, such that an output end of the mute controlcircuit used upon power-on or power-off outputs high voltage level tothe mute circuit to control the mute circuit be activated.

Further, in the audio device, after the first capacitor is chargedcompletely, the first triode is in a turned-off state due to voltageincrease of the base electrode of the first triode, and the collectorelectrode of the first triode outputs low voltage level to the secondtriode such that the second triode is in the turned-off state, therebycontrolling the output end of the mute control circuit used uponpower-on or power-off to output low voltage level to the mute circuit.

Further, in the audio device, upon power-off at the power supply end,the second capacitor can perform discharging only via the third resistorand the first triode due to an isolation function of the first diode,and the first capacitor completely releases electric charges immediatelyvia the second diode such that the base electrode of the first triode isat low voltage level, since the emitter electrode of the first triode isat high voltage level under the discharging of the second capacitor, thefirst triode is controlled to be in the turned-on state and thecollector electrode of the first triode is at high voltage level, suchthat the second triode is in the turned-on state and both of the emitterelectrode and the collector electrode of the second triode are at highvoltage level, thereby making an output end of the mute control circuitused upon power-on or power-off outputs high voltage level to the mutecircuit to control the mute circuit to be activated.

Further, in the audio device, after the second capacitor dischargescompletely, the first triode is in a turned-off state due to voltagedecrease of the emitter electrode of the first triode, and the collectorelectrode of the first triode outputs low voltage level to the secondtriode such that the second triode is in the turned-off state, therebycontrolling the output end of the mute control circuit used uponpower-on or power-off to output low voltage level to the mute circuit.

BENEFICIAL EFFECTS

The present invention discloses a mute control circuit used uponpower-on or power-off, a control method and an audio device, the mutecontrol circuit used upon power-on or power-off is connected to a powersupply end and a mute circuit of the audio device, the mute controlcircuit used upon power-on or power-off includes a charge/dischargemodule, a first switch module and a second switch module; thecharge/discharge module is charged from the power supply end uponpower-on, the charge/discharge module discharges into the power supplyend upon power-off, the charge/discharge module outputs a first level tothe first switch module upon charging or discharging to control thefirst switch module to be in a turned-on state, the first switch moduleoutputs a second level to the second switch module to control the secondswitch module to be in the turned-on state, the second switch moduleoutputs high voltage level to the mute circuit to control the mutecircuit to be activated. As long as a low-cost and easily controlledcircuit is adopted, the high voltage level can be outputted to the mutecircuit during power-on and power-off processes to control the mutecircuit to be activated, thereby eliminating the pop sound generatedupon power-on and power-off and improving user experience on the audiodevice.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a structural block diagram showing a mute control circuit usedupon power-on or power-off provided in an embodiment of the presentinvention.

FIG. 2 is a circuit diagram showing a mute control circuit used uponpower-on or power-off provided in an embodiment of the presentinvention.

FIG. 3 is a diagram showing a voltage output simulation result uponpower-on for the mute control circuit used upon power-on or power-offprovided in an embodiment of the present invention.

FIG. 4 is a diagram showing a voltage output simulation result uponpower-off for the mute control circuit used upon power-on or power-offprovided in an embodiment of the present invention.

FIG. 5 is a flowchart of a mute control method used upon power-on orpower-off provided in an embodiment of the present invention.

DETAILED DESCRIPTION

In view of drawbacks of existing audio devices for generation of popsound upon power-on or power-off, the objective of the present inventionis to provide a mute control circuit used upon power-on or power-off, acontrol method and an audio device, in which a low-cost and easilycontrolled circuit is adopted to be able to output high voltage level toa mute circuit upon power-on and power-off to control the mute circuitto be activated, thereby eliminating the pop sound generated uponpower-on or power-off, and improving user experience on the audiodevices.

To make the objectives, technical schemes, and effects of the presentinvention clearer and more specific, the present invention is describedin further detail below with reference to the embodiments inaccompanying with the appending drawings. It should be understood thatthe specific embodiments described herein are merely for interpretingthe present invention and the present invention is not limited thereto.

Referring to FIG. 1, a mute control circuit 100 used upon power-on orpower-off, provided in the present invention, is connected to a powersupply end and a mute circuit 200 of an audio device. The power supplyend can be a VCC power supply end. The mute control circuit 100 includesa charge/discharge module 10, a first switch module 11 and a secondswitch module 12. All of the charge/discharge module 10, the firstswitch module 11 and the second switch module 12 are connected to theVCC power supply end of the audio device, and the charge/dischargemodule 10, the first switch module 11 and the second switch module 12are sequentially connected to each other. The second switch module 12 isfurther connected to the mute circuit 200. An operation state of themute circuit 200 is controlled by a voltage signal outputted by thesecond switch module 12, thereby activating or deactivating the mutecircuit 200.

Specifically, upon the audio device is powered on, the VCC power supplyend provides a direct-current (DC) power supply voltage to the mutecontrol circuit 100 and meanwhile, the charge/discharge module 10 isbeing charged. Upon the audio device is powered off, electricity storedin the charge/discharge module 10 will be released and meanwhile, thecharge/discharge module 10 is discharging. Upon power-on charging orpower-off discharging, the charge/discharge module 10 outputs a firstlevel to the first switch module 11 to control the first switch module11 to be in a turned-on state. After that, the first switch module 11outputs a second level to the second switch module 12 to control thesecond switch module 12 to be in the turned-on state, such that thesecond switch module 12 outputs high voltage level to the mute circuit200 to control the mute circuit 200 to be activated, thereby eliminatingthe pop sound generated upon power-on and power-off, solving the problemthat mute cannot be realized during power-on and power-off processes dueto uncontrollable controller input/output (10) port, and improving userexperience.

In the present embodiment, the first level is low voltage level and thesecond level is high voltage level. Of course, this may be adjusted inother embodiments according to actual needs. The present invention isnot limited thereto, as long as it is able to control the second switchmodule 12 to output high voltage level to the mute circuit 200 to makeit function normally.

Further, also referring to FIG. 2, the charge/discharge module 10includes a charge/discharge unit 101 and a separation unit 102. Theseparation unit 102 is connected to the charge/discharge unit 101. Thecharge/discharge unit 101 is connected to the first switch module 11.Upon power-on and power-off, the separation unit 102 controls a chargingcurrent direction and a discharging current direction. Thecharge/discharge unit 101 performs charging or discharging according tothe charging current direction and the discharging current direction.That is, by deploying the separation unit 102, the present inventioncontrols the current directions during charging and discharging,guarantees that charge/discharge unit 101 performs the charging ordischarging based on the preset directions and makes sure accuracy of avoltage signal outputted to the first switch module 11, thereby ensuringthe mute circuit 200 be able to operate normally upon power-on andpower-off, eliminating the pop sound generated during power-on andpower-off processes, and improving reliability of the product.

Specifically, the charge/discharge unit 101 includes a first capacitorC1 and a second capacitor C2. The separation unit 102 includes a firstdiode D1, a second diode D2 and a first resistor R1. A positiveelectrode of the first diode D1 is connected to a negative electrode ofthe second diode D2, one end of the first resistor R1 and the VCC powersupply end. The negative electrode of the first diode D1 is connected tothe first switch module 11 and the second switch module 12, and isfurther grounded via the second capacitor C2. The positive electrode ofthe second diode D2 is connected to the other end of the first resistorR1 and the first switch module 11, and is further grounded via the firstcapacitor C1.

Upon power-on at the VCC power supply end, the first capacitor C1 ischarged from the VCC power supply end via the first resistor R1 and thesecond capacitor C2 is charged from the VCC power supply end via thefirst diode D 1. Low voltage level is outputted to the first switchmodule 11 during charging the first capacitor C1. Upon power-off at theVCC power supply end, a discharging path from the second capacitor C2 tothe VCC power supply end is isolated due to an isolation function of thefirst diode D1. Accordingly, electric charges in the second capacitor C2are discharged through the first switch module 11, and the electriccharges in the first capacitor C1 are quickly released through thesecond diode D2, such that a voltage signal outputted to the firstswitch module 11 is at low voltage level, thereby controlling the firstcapacitor C1 and the second capacitor C2 to perform charging ordischarging according to a preset path. In such a way, no matterpower-on or power-off, the voltage signal outputted to the first switchmodule 11 is always a low voltage signal, which controls the firstswitch module 11 to be turned on to further control subsequent signaloutput, thereby ensuring the mute circuit 200 be able to be activatedimmediately, eliminating the pop sound during power-on and power-offprocesses, and making sure mute effect of the audio device upon power-onand power-off.

Further, the first switch module 11 includes a second resistor R2, athird resistor R3 and a first triode Q1. One end of the second resistorR2 is connected to the positive electrode of the second diode D2 and theother end of the second resistor R2 is connected to a base electrode ofthe first triode Q1. An emitter electrode of the first triode Q1 isconnected to one end of the third resistor R3 and the other end of thethird resistor R3 is connected to the negative electrode of the firstdiode D1. A collector electrode of the first triode Q1 is connected tothe second switch module 12. In the present embodiment, the first triodeQ1 is a PNP triode.

The second switch module 12 includes a fourth resistor R4, a fifthresistor R5 and a second triode R2. One end of the fourth resistor R4 isconnected to the collector electrode of the first triode Q1 and theother end of the fourth resistor R4 is connected to the base electrodeof the second triode Q2. The collector electrode of the second triode Q2is connected to the negative electrode of the first diode D1 and theemitter electrode of the second triode Q2 is connected to one end of thefifth resistor R5 and the mute circuit 200. The other end of the fifthresistor R5 is grounded. In the present embodiment, the second triode Q2is an NPN triode.

As described above, no matter when the first capacitor C1 and the secondcapacitor C2 are in a charging state upon power-on or when the firstcapacitor C1 and the second capacitor C2 are in a discharging state uponpower-off, the voltage signal inputted to the first triode Q1 via thesecond resistor R2 is always at low voltage level.

Upon power-on, the voltage signal inputted to the base electrode of thefirst triode Q1 is at low voltage level, and a power supply voltage atthe VCC power supply end reaches the emitter electrode of the firsttriode Q1 via the first diode D1 and the third resistor D3. When avoltage difference between the emitter electrode and the base electrodeis greater than 0.7V, the turned-on state maintains for the first triodeQ1 and meanwhile, voltages of the collector electrode of the firsttriode Q1 connected to the base electrode of the second triode Q2 andthe emitter electrode of the first triode Q1 are equal to each other andare both at high voltage level. That is, the first switch module 11outputs high voltage level to the second switch module 12. Since theemitter electrode of the second triode Q2 is pulled down to the ground,the second triode Q2 is also in the turned-on state, and voltages of theemitter electrode and the collector electrode of the second triode areequal to each other and are both at high voltage level. That is, anoutput end Out_put of the mute control circuit 100 used upon power-on orpower-off outputs high voltage level to the mute circuit 200 to controlthe mute circuit 200 be activated. After the first capacitor C1 ischarged completely, the first triode Q1 is in a turned-off state due tovoltage increase of the base electrode of the first triode Q1, and thecollector electrode of the first triode Q1 outputs low voltage level tothe second triode Q2 such that the second triode Q2 is also in theturned-off state, thereby controlling the output end Out_put to outputlow voltage level to the mute circuit 200.

In the embodiments of the present invention, a power-on voltage outputsimulation result is shown in FIG. 3, where label “1” indicates a VCCvoltage and label “2” indicates a voltage at the output end Out_put. Itcan be seen that the signal at the output end Out_put of the mutecontrol circuit 100 is instantly changed to high voltage level uponpower-on and is kept at the high voltage level for a certain period oftime, and after that, is changed to be at low voltage level. For theperiod of time the high voltage level is maintained, the pop sound iseliminated by the mute circuit 200, thereby improving the mute effectupon power-on. The capacitance of the first capacitor C1 and theresistance of the first resistor R1 determines the period of time thehigh voltage level is maintained. This can be adjusted based on actualneeds to satisfy different application scenarios.

Upon power-off, the second capacitor C2 can perform discharging only viathe third resistor R3 and the first triode Q1 due to the isolationfunction of the first diode D1. During power-off at VCC, the firstcapacitor C1 completely releases electric charges immediately via thesecond diode D2 such that the base electrode of the first triode Q1 isat low voltage level. Since the emitter electrode of the first triode Q1is at high voltage level under the discharging of the second capacitorC2, the first triode Q1 is in the turned-on state and the collectorelectrode of the first triode Q1 is also at high voltage level, suchthat the second triode Q2 is in the turned-on state and voltages of theemitter electrode, and the collector electrode of the second triode Q2are equal to each other and are both at high voltage level. That is, theoutput end Out_put of the mute control circuit 100 outputs high voltagelevel to the mute circuit 200 to control the mute circuit 200 to beactivated. After the second capacitor C2 discharges completely, thefirst triode Q1 is in a turned-off state due to voltage decrease of theemitter electrode, and the collector electrode outputs low voltage levelto the second triode Q2 such that the second triode Q2 is also in theturned-off state, thereby controlling the output end Out_put to outputlow voltage level to the mute circuit 200.

In the embodiments of the present invention, a power-off voltage outputsimulation result is shown in FIG. 4, where label “1” indicates a VCCvoltage and label “2” indicates a voltage at the output end Out_put. Itcan be seen that the signal at the output end Out_put of the mutecontrol circuit 100 is instantly changed to high voltage level uponpower-off and is kept at the high voltage level for a certain period oftime, and after that, is changed to be at low voltage level. For theperiod of time the high voltage level is maintained, the pop sound iseliminated by the mute circuit 200, thereby improving the mute effectupon power-off. The capacitance of the second capacitor C2 and theresistance of the first resistor R1 determines the period of time thehigh voltage level is maintained. This can be adjusted based on actualneeds to satisfy different application scenarios.

Based on the afore-described mute control circuit used upon power-on orpower-off, the present invention further correspondingly provides a mutecontrol method used upon power-on or power-off. As shown in FIG. 5, themute control method includes steps of:

Step S100—upon power-on charging or power-off discharging, utilizing acharge/discharge module to output a first level to a first switch moduleto control the first switch module to be in a turned-on state;

Step S200—utilizing the first switch module to output a second level toa second switch module to control the second switch module to be in theturned-on state;

Step S300—utilizing the second switch module to output high voltagelevel to a mute circuit to control the mute circuit to be activated.Based on the afore-described mute control circuit used upon power-on orpower-off, the present invention further correspondingly provides anaudio device including a power supply end, a mute circuit and theafore-described mute control circuit used upon power-on or power-off.The mute control circuit used upon power-on or power-off has beendescribed detailedly above, and is not repeated herein.

Above all, in the mute control circuit used upon power-on or power-off,the control method and an audio device provided in the presentinvention, the mute control circuit used upon power-on or power-off isconnected to a power supply end and a mute circuit of the audio device,the mute control circuit used upon power-on or power-off includes acharge/discharge module, a first switch module and a second switchmodule; the charge/discharge module is charged from the power supply endupon power-on, the charge/discharge module discharges into the powersupply end upon power-off, the charge/discharge module outputs a firstlevel to the first switch module upon charging or discharging to controlthe first switch module to be in a turned-on state, the first switchmodule outputs a second level to the second switch module to control thesecond switch module to be in the turned-on state, the second switchmodule outputs high voltage level to the mute circuit to control themute circuit to be activated. As long as a low-cost and easilycontrolled circuit is adopted, the high voltage level can be outputtedto the mute circuit during power-on and power-off processes to controlthe mute circuit to be activated, thereby eliminating the pop soundgenerated upon power-on and power-off and improving user experience onthe audio device.

It should be understood that those of ordinary skill in the art may makeequivalent modifications or variations according to the technicalschemes and invention concepts of the present invention, but all suchmodifications and variations should be within the appended claims.

1. A mute control circuit used upon power-on or power-off, connected toa power supply end and a mute circuit of an audio device, the mutecontrol circuit comprising: a charge/discharge module, charged from thepower supply end upon power on and discharging into the power supply endupon power-off; a first switch module, connected to the charge/dischargemodule, wherein upon charging or discharging, the charge/dischargemodule outputs a first level to the first switch module to control thefirst switch module to be in a turned-on state; and a second switchmodule, connected to the first switch module, wherein upon charging ordischarging, the first switch module outputs a second level to thesecond switch module to control the second switch module to be in theturned-on state, and the second switch module outputs high voltage levelto the mute circuit to control the mute circuit to be activated, whereinthe charge/discharge module comprises a charge/discharge unit and aseparation unit, the charge/discharge unit comprises a first capacitorand a second capacitor, and the separation unit comprises a first diode,a second diode and a first resistor, wherein a positive electrode of thefirst diode is connected to a negative electrode of the second diode,one end of the first resistor and the power supply end, the negativeelectrode of the first diode is connected to the first switch module andthe second switch module and is further grounded via the secondcapacitor; the positive electrode of the second diode is connected tothe other end of the first resistor and the first switch module and isfurther grounded via the first capacitor, wherein upon power-on at thepower supply end, the first capacitor is charged from the power supplyend via the first resistor and the second capacitor is charged from thepower supply end via the first diode, low voltage level is outputted tothe first switch module during charging the first capacitor; uponpower-off at the power supply end, a discharging path from the secondcapacitor to the power supply end is isolated due to an isolationfunction of the first diode, such that electric charges in the secondcapacitor are discharged through the first switch module, and theelectric charges in the first capacitor are released through the seconddiode, making a voltage signal outputted to the first switch module atlow voltage level, thereby controlling the first capacitor and thesecond capacitor to perform charging or discharging according to apreset path.
 2. The mute control circuit according to claim 1, whereinthe separation unit controls a charging current direction and adischarging current direction upon power-on and power-off, thecharge/discharge unit performs charging or discharging based on thecharging current direction and the discharging current direction. 3.(canceled)
 4. The mute control circuit according to claim 1, wherein thefirst switch module comprises a second resistor, a third resistor and afirst triode; one end of the second resistor is connected to thepositive electrode of the second diode and the other end of the secondresistor is connected to a base electrode of the first triode; anemitter electrode of the first triode is connected to one end of thethird resistor and the other end of the third resistor is connected tothe negative electrode of the first diode, a collector electrode of thefirst triode is connected to the second switch module.
 5. The mutecontrol circuit according to claim 4, wherein the second switch modulecomprises a fourth resistor, a fifth resistor and a second triode; oneend of the fourth resistor is connected to the collector electrode ofthe first triode and the other end of the fourth resistor is connectedto the base electrode of the second triode; the collector electrode ofthe second triode is connected to the negative electrode of the firstdiode and the emitter electrode of the second triode is connected to oneend of the fifth resistor and the mute circuit; the other end of thefifth resistor is grounded.
 6. The mute control circuit according toclaim 4, wherein the first triode is a PNP triode.
 7. The mute controlcircuit according to claim 5, wherein the second triode is an NPNtriode.
 8. A mute control method used upon power-on or power-off,comprising steps of: upon power-on charging or power-off discharging,utilizing a charge/discharge module to output a first level to a firstswitch module to control the first switch module to be in a turned-onstate; utilizing the first switch module to output a second level to asecond switch module to control the second switch module to be in theturned-on state; and utilizing the second switch module to output highvoltage level to a mute circuit to control the mute circuit to beactivated, wherein the charge/discharge module comprises acharge/discharge unit and a separation unit, the charge/discharge unitcomprises a first capacitor and a second capacitor, and the separationunit comprises a first diode, a second diode and a first resistor,wherein a positive electrode of the first diode is connected to anegative electrode of the second diode, one end of the first resistorand a power supply end, the negative electrode of the first diode isconnected to the first switch module and the second switch module and isfurther grounded via the second capacitor; the positive electrode of thesecond diode is connected to the other end of the first resistor and thefirst switch module and is further grounded via the first capacitor,wherein upon power-on at the power supply end, the first capacitor ischarged from the power supply end via the first resistor and the secondcapacitor is charged from the power supply end via the first diode, lowvoltage level is outputted to the first switch module during chargingthe first capacitor; upon power-off at the power supply end, adischarging path from the second capacitor to the power supply end isisolated due to an isolation function of the first diode, such thatelectric charges in the second capacitor are discharged through thefirst switch module, and the electric charges in the first capacitor arereleased through the second diode, making a voltage signal outputted tothe first switch module at low voltage level, thereby controlling thefirst capacitor and the second capacitor to perform charging ordischarging according to a preset path.
 9. An audio device, comprising apower supply end, a mute circuit and a mute control circuit used uponpower-on or power-off, the mute control circuit connected to the powersupply end and the mute circuit, the mute control circuit comprising: acharge/discharge module, charged from the power supply end upon power onand discharging into the power supply end upon power-off; a first switchmodule, connected to the charge/discharge module, wherein upon chargingor discharging, the charge/discharge module outputs a first level to thefirst switch module to control the first switch module to be in aturned-on state; and a second switch module, connected to the firstswitch module, wherein the first switch module outputs a second level tothe second switch module to control the second switch module to be inthe turned-on state, and the second switch module outputs high voltagelevel to the mute circuit to control the mute circuit to be activated,wherein the charge/discharge module comprises a charge/discharge unitand a separation unit, the charge/discharge unit comprises a firstcapacitor and a second capacitor, and the separation unit comprises afirst diode, a second diode and a first resistor, wherein a positiveelectrode of the first diode is connected to a negative electrode of thesecond diode, one end of the first resistor and a power supply end, thenegative electrode of the first diode is connected to the first switchmodule and the second switch module and is further grounded via thesecond capacitor; the positive electrode of the second diode isconnected to the other end of the first resistor and the first switchmodule and is further grounded via the first capacitor, wherein uponpower-on at the power supply end, the first capacitor is charged fromthe power supply end via the first resistor and the second capacitor ischarged from the power supply end via the first diode, low voltage levelis outputted to the first switch module during charging the firstcapacitor; upon power-off at the power supply end, a discharging pathfrom the second capacitor to the power supply end is isolated due to anisolation function of the first diode, such that electric charges in thesecond capacitor are discharged through the first switch module, and theelectric charges in the first capacitor are released through the seconddiode, making a voltage signal outputted to the first switch module atlow voltage level, thereby controlling the first capacitor and thesecond capacitor to perform charging or discharging according to apreset path.
 10. The audio device according to claim 9, wherein theseparation unit controls a charging current direction and a dischargingcurrent direction upon power-on and power-off, the charge/discharge unitperforms charging or discharging based on the charging current directionand the discharging current direction.
 11. The audio device according toclaim 10, wherein the-first level is low voltage level and the secondlevel is high voltage level.
 12. (canceled)
 13. The audio deviceaccording to claim 9, wherein the first switch module comprises a secondresistor, a third resistor and a first triode; one end of the secondresistor is connected to the positive electrode of the second diode andthe other end of the second resistor is connected to a base electrode ofthe first triode; an emitter electrode of the first triode is connectedto one end of the third resistor and the other end of the third resistoris connected to the negative electrode of the first diode, a collectorelectrode of the first triode is connected to the second switch module.14. The audio device according to claim 13, wherein the second switchmodule comprises a fourth resistor, a fifth resistor and a secondtriode; one end of the fourth resistor is connected to the collectorelectrode of the first triode and the other end of the fourth resistoris connected to the base electrode of the second triode; the collectorelectrode of the second triode is connected to the negative electrode ofthe first diode and the emitter electrode of the second triode isconnected to one end of the fifth resistor and the mute circuit; theother end of the fifth resistor is grounded.
 15. The audio deviceaccording to claim 14, wherein the first triode is a PNP triode.
 16. Theaudio device according to claim 15, wherein the second triode is an NPNtriode.
 17. The audio device according to claim 16, wherein uponpower-on at the power supply end, a voltage signal inputted to the baseelectrode of the first triode is at low voltage level, a power supplyvoltage at the power supply end reaches the emitter electrode of thefirst triode via the first diode and the third resistor, when a voltagedifference between the emitter electrode and the base electrode of thefirst triode is greater than 0.7V, the turned-on state maintains for thefirst triode and both of voltages of the collector electrode of thefirst triode connected to the base electrode of the second triode andthe emitter electrode of the first triode are at high voltage level suchthat the first switch module outputs high voltage level to the secondswitch module; since the emitter electrode of the second triode isgrounded, the second triode is controlled to be in the turned-on stateand both of voltages of the emitter electrode and the collectorelectrode of the second triode are at high voltage level, such that anoutput end of the mute control circuit used upon power-on or power-offoutputs high voltage level to the mute circuit to control the mutecircuit be activated.
 18. The audio device according to claim 17,wherein after the first capacitor is charged completely, the firsttriode is in a turned-off state due to voltage increase of the baseelectrode of the first triode, and the collector electrode of the firsttriode outputs low voltage level to the second triode such that thesecond triode is in the turned-off state, thereby controlling the outputend of the mute control circuit used upon power-on or power-off tooutput low voltage level to the mute circuit.
 19. The audio deviceaccording to claim 16, wherein upon power-off at the power supply end,the second capacitor can perform discharging only via the third resistorand the first triode due to an isolation function of the first diode,and the first capacitor completely releases electric charges immediatelyvia the second diode such that the base electrode of the first triode isat low voltage level, since the emitter electrode of the first triode isat high voltage level under the discharging of the second capacitor, thefirst triode is controlled to be in the turned-on state and thecollector electrode of the first triode is at high voltage level, suchthat the second triode is in the turned-on state and both of the emitterelectrode and the collector electrode of the second triode are at highvoltage level, thereby making an output end of the mute control circuitused upon power-on or power-off outputs high voltage level to the mutecircuit to control the mute circuit to be activated.
 20. The audiodevice according to claim 19, wherein after the second capacitordischarges completely, the first triode is in a turned-off state due tovoltage decrease of the emitter electrode of the first triode, and thecollector electrode of the first triode outputs low voltage level to thesecond triode such that the second triode is in the turned-off state,thereby controlling the output end of the mute control circuit used uponpower-on or power-off to output low voltage level to the mute circuit.